Incapacitation of a pilot due to the effects of a medical condition or a physiological impairment represents a serious potential threat to flight safety. The purpose of this research project was to investigate the prevalence, type, nature and significance of in-flight medical conditions and incapacitation events occurring in civil aviation. A search of the Australian Transport Safety Bureau's accident and incident database was conducted for medical conditions and incapacitation events between 1 January 1975 and 31 March 2006. There were 98 occurrences in which the pilot of the aircraft was incapacitated for medical or physiological reasons (16 accidents, one serious incident and 81 incidents). Such events accounted for only 0.6 of a percentage point of all the occurrences listed in the Australian Transport Safety Bureau's database. The majority of the events occurred in airline operations, with private flying the next most common (22.4 per cent of events). In 10 occurrences (10.2 per cent), the outcome of the event was a fatal accident. All of these accidents involved single-pilot operations, and in the majority of cases, heart attack was the most common cause. The majority (21 per cent) of in-flight medical and incapacitation events in Australian civil pilots for the study period were due to acute gastrointestinal illness (usually food poisoning), a finding consistent with other published studies. The next most common cause was exposure to toxic smoke and fumes on board the aircraft, of which 25 per cent were due to carbon monoxide. The results of this study demonstrate that the risk of a pilot suffering from an in-flight medical condition or incapacitation event is low. However, if the pilot suffers a heart attack the risk of a fatal accident occurring increases. The aeromedical certification process must keep pace with the evolving nature of modern medical science to ensure that the risk of in-flight incapacitation remains low.

Spatial disorientation (SD) is among the most common factors contributing to aviation accidents and incidents, but its true prevalence is difficult to establish. This is because many accidents where SD is cited as a likely factor are fatal, and therefore its role cannot be known with any certainty, but also because in the many instances of SD where an accident doesn't result, it goes unreported.

This study provides a comprehensive explanation of the various types of SD in the aviation environment, and suggest strategies for managing the risk associated with SD events. This report provides an informative overview of the three basic types of SD, and the circumstances under which disorientation might be more likely. These are of value to all pilots, and especially those who conduct flights in instrument conditions or at night under visual flight rules. Single-pilot operations, particularly where an autopilot is not available, face additional risks and the need to identify and manage SD events.

This report also encourages pilots who have experienced SD episodes to share their experiences with their aviation colleagues, either informally, or through magazines, journals and web-based forums. This will serve to encourage a greater awareness of the incidence of SD, and help reduce the stigma that some pilots might associate with these events. As other studies suggest, SD is likely to be encountered by all pilots during the course of a lifetime's flying - whether professional or non-professional, experienced or inexperienced. A more open approach to acknowledging and discussing SD and its various causes will make a valuable contribution to a better understanding of this common human factor.

The 1995 House of Representatives Standing Committee on Transport, Communications and Infrastructure Plane Safe Report (Morris, 1995), found that 'a paucity of information' and 'an absence of safety indicators' were features of the low-capacity RPT sector of the Australian aviation industry. A Preliminary Information Paper published by BASI in 1996 concluded that a range of safety issues warranting further research existed within the regional airline industry. BASI then appointed a research team to comprehensively investigate the level of safety in the regional airline industry.

After a study of safety occurrences in the BASI database and visits to many regional airlines, a safety questionnaire was sent to every member of the regional airline industry. More than 28% of industry members responded to the survey.

The study examined all areas of the regional airlines operations, including cabin safety, flight operations, maintenance, airspace management, regulations and surveillance.

Overall, the results indicated that in 1996-97 the safety health of the industry was good, although some areas for improvement were identified. Ninety-two per cent of respondents rated the safety of their regional airline as adequate or better. On the other hand, 57% of respondents identified reasons for avoiding some regional airlines. The results showed that there was an industry wide awareness of the importance of a good safety culture.

Where a safety deficiency was identified by this study, safety action, in the form of a recommendation or a safety advisory notice, was taken by BASI. A summary of the safety action taken prior to the release of this report is contained in chapter 6.

This study was conducted with the support of the industry and shows that, on the whole, the industry does have a high regard for safety. However, it was found that in some airlines, commercial pressures were a significant factor in many safety deficiencies.

Note: The Bureau recognises that a number of changes have occurred within aspects of the aviation industry between the time the Regional Airlines Safety Study commenced and the release of this report. The findings of the study, as summarised in chapter 5 of this report, are based on the 1996-97 structure and climate of the aviation industry. Every effort has been made to acknowledge relevant changes.

Communication within the air traffic system relies heavily on the verbal interaction between pilots and air traffic controllers (controllers) to ensure the safe and efficient operation of air traffic. The use of standard phraseology and radio telephony procedures, such as readbacks, minimises the opportunity for misinterpretation between pilot and controller.

Some sectors of the industry have raised concerns regarding the use of excess or non-standard phraseology in readbacks on the surface movement control (SMC) frequency, resulting in radio congestion. The purpose of this report was to explore the relationship between excess or nonstandard words in readbacks and its effect on frequency congestion.

A review of the Sydney SMC frequency tapes concluded that most users complied with the readback requirements stipulated in the Aeronautical Information Publication (AIP), with only the occasional radio transmission containing excess or non-standard verbiage. Overall, the tapes identified a high level of compliance with the AIP readback requirements; however, it was noted that the use of pleasantries was commonplace. While these did not appear to affect frequency congestion adversely, in times of high traffic density it seems inappropriate.

This study provides a systematic analysis of the types of human error occurring in Australian civil aviation accidents. It also compares these results against a larger sample of accidents occurring in the United States. Inevitably, all humans make errors. But safety can be enhanced when the number and consequences of these errors are reduced. This paper aims to enhance aviation safety through extending our knowledge of aircrew errors.

While the types of accidents and flying operations varied slightly between Australia and the US, the pattern of aircrew errors were remarkably similar. Skill-based errors were the most prevalent type of aircrew unsafe act, followed by decision errors, violations and perceptual errors in both Australian and US accidents. Skill-based errors were also the most common error type irrespective of the severity of the accident. In Australia, decision errors and violations were more common in fatal accidents.

The trend data indicated that the proportion of accidents associated with skill-based errors did not change over the period studied, but decision errors decreased.

The distribution of unsafe acts across flying operation type indicated that skill-based errors were disproportionately higher in both general aviation and agricultural operations. Charter operations (called on-demand in the US) had a high proportion of violations and decision errors. The pattern of unsafe acts within each type of flying operation was broadly similar for Australian and US accidents.

The study demonstrated that the greatest gains in reducing aviation accidents could be achieved by reducing skill-based errors. Moreover, improvements in aeronautical decision making and the modification of risk-taking behaviour could reduce aviation fatalities. Further study is needed to both identify which particular skills need improving, and to investigate the importance of interactions between the error categories.

Following three breakdown of separation occurrences in the airspace of the Sydney Terminal Area (TMA), the Bureau of Air Safety Investigation (BASI) initiated a systemic investigation into the common factors underlying those occurrences. The investigation commenced on 22 June 1998 and was completed by 31 July 1998. Three further occurrences were identified during the course of the investigation.

The systemic investigation has identified safety deficiencies primarily related to the management of change, and the rate and complexity of change faced by air traffic controllers operating in the Sydney Terminal Control Unit over the last four years. Resolving these management issues will further enhance the safe operation of aircraft in the airspace of the Sydney Terminal area. This report contains nine safety recommendations that have been developed to address identified safety deficiencies.

The Robinson R22 helicopter is the most common model of rotary-wing aircraft on the Australian register and has been a popular choice for private operations, flying training and various types of aerial work activity. The R22 has a relatively good safety record compared with other light piston-engine helicopters in Australia based on activity levels.

The R22 is also the favoured type for aerial stock mustering operations - a uniquely Australian application that supports the local beef cattle industry. Despite its popularity in this type of work, little was known about the helicopter's suitability for the task. Like other helicopters on the Australian register, the R22 received its initial airworthiness certification in its country of manufacture (United States). The spectrum of manoeuvres conducted in aerial stock mustering did not form part of the flight profile used when the helicopter type received its certification.

In 2004 the ATSB commissioned AeroStructures, an Australian engineering company, to undertake a study of forces acting on an R22 engaged in aerial mustering operations. AeroStructures Report:

Their study offers some useful data on R22 flight profiles in aerial mustering operations, and compares these with the flight profiles used by Robinson Helicopter Company when the helicopter was initially certified.

The AeroStructures testing showed that mustering operations can involve large and sudden power changes that apply very high loads on the helicopter's drive system, and these may exceed the limits set during the certification process. Their report highlights the importance of handling technique, and especially good engine management.

This aim of the study was to provide objective data to inform fatigue risk-management processes by determining the quantity and quality of sleep obtained by airline pilots during transcontinental back of clock operations, and any changes to subjective fatigue and neurobehavioral performance during these sectors. Typical transcontinental back of clock route pairings involve a departure close to midnight Perth local time, with a dawn arrival into an East-coast city such as Melbourne, Sydney or Brisbane. In many instances this first sector is followed by a second sector to another east-coast destination, with sign-off at approximately 0900 Eastern Standard Time. Data were collected by participants during a two-week period of a normal rostered flying for an airline. During each of the 14 days of data collection, participants were required to undertake the following:

1. Wear an activity monitor wristwatch 7 days prior to, and 6 days after, a transcontinental back of clock flight;
2. complete sleep and duty diaries, which record time of sleep, subjective alertness, and time of duty; and
3. complete a simple 5-minute Psychomotor Vigilance Task (reaction time task) during the cruise of each sector, and three times on non-flying days.

The results of this study suggest that Australian transcontinental back of clock operations, as operated by the airline involved in this study, differed significantly from a baseline sample of daytime duty periods in a number of important areas with respect to prior sleep, neurobehavioral performance, and subjective fatigue. While there were some significant differences in sleep and subjective fatigue as a function of a single transcontinental sector of back of clock flying, these differences were, on average, of a magnitude that was unlikely to impact on flight crew performance and overall safety. However, when a primary transcontinental sector is followed by an additional east-coast sector, there is evidence of reduced prior sleep, impaired neurobehavioral performance, and high levels of subjective fatigue.

Each year the United States' Aircraft Owner's and Pilots Association (AOPA) Air Safety Foundation releases a report summarising the accident trends and factors for general aviation (GA) for the previous calendar year. The Nall Report has established itself as one of the aviation community's benchmark reports and its release is anticipated across the industry. The report provides essential data in an easy-to-read format, giving a broad overview of the state of general aviation and safety trends in the US.

As part of the Australian Transport Safety Bureau's (ATSB) mission to enhance public awareness of aviation safety, the Australian Aviation Safety in Review - 2007 has been developed to provide a readily accessible analysis of the Australian aviation sector, with a strong focus on safety trends. Unlike the Nall Report, this publication covers all major categories of aircraft operations, from Regular Public Transport (RPT) to general aviation, and even some information about sports aviation.

Additionally, some demographic data on Australian aviation is provided in order to measure the levels of aviation activity in Australia, and provide a context within which to examine the accident trends. Accident rates are presented both in terms of the number of accidents and as rates per 100,000 hours, to enable comparison between operational categories. The latest year for which flying hours are available is 2005. Accordingly, this inaugural edition of the Australian Aviation Safety in Review - 2007 covers the calendar years 2001 to 2005, offering insights and information about key trends and emerging issues.

The ATSB intends to release this report on a regular basis as a means of informing both the aviation community and the wider public about Australian aviation accident and activity trends.

Regional airline operations globally have expanded over the past decade for various reasons, including filling gaps left by legacy carriers who have reduced services on unprofitable routes, opportunities provided through other cost based market rationalisations, and the introduction of new and more capable regional type aircraft. Very little formal research has been done in Australia or overseas to assist with the development of safety models and tools for regional airline operations. Regional Express (REX) is a relatively new airline that was created by merging two separate and culturally different airline entities. After a post start-up initial settling in period, REX needed a new tool to further develop safety-based auditing for its newly combined flight operations department. The Line Operations Safety Audit (LOSA) offered through the University of Texas LOSA Collaborative, provided an effective tool for this purpose. Around the time REX was reviewing its need in this area, the LOSA Collaborative was confirming an interest in conducting research with regional airlines. The LOSA Collaborative wished to obtain data from regional airlines to add to its LOSA Archive database in order to move toward making the database more representative and the LOSA tools more relevant for use in the regional airline environment. The LOSA Collaborative set out to attract three regional airline participants to add their data through the LOSA process. Regional Express was successful in attracting funding under the Australian Transport Safety Bureaus Aviation Safety Research Grants Program to undertake the LOSA process. Completion of this project has added to the expansion of the LOSA database to include regional airline data. This report describes the LOSA process as it applies within the regional airline context of REX and the reported outcome types specific to the LOSA methodology, process, and tools. Regional Express is one of the first regional airlines globally to participate in a LOSA program.